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 Page 1


 
 
SECTION  - A 
 
1. Match List I with List II. 
 List I    List II 
(a) Rectifier   (i) Used either for stepping up or stepping down the a.c. 
                    Voltage 
(b) Stabilizer   (ii) Used to convert a.c. voltage into d.c. voltage 
(c) Transformer   (iii) Used to remove any ripple in the rectified output voltage 
(d)  Filter    (iv) Used for constant output voltage even when the input 
voltage or load current change 
Choose the correct answer form the options given below: 
(1) (a)-(ii), (b)- (i), (c)-(iv), (d)-(iii) 
(2) (a)-(ii), (b)- (iv), (c)-(i), (d)-(iii)  
(3) (a)-(ii), (b)- (i), (c)-(iii), (d)-(iv) 
(4) (a)-(iii), (b)- (iv), (c)-(i), (d)-(ii) 
Sol. 2 
(a)Rectifier:- used to convert a.c voltage into d.c. Voltage. 
(b) Stabilizer:- used for constant output voltage even when the input voltage or load current 
change 
(c) Transformer:- used either for stepping up or stepping down the a.c. voltage. 
(d) Filter:- used to remove any ripple in the rectified output voltage. 
  
2. Y = A sin( ?t + ?
0
) is the time – displacement equation of a SHM, At t = 0 the displacement of 
the particle is Y = 
A
2
 and it is moving along negative x-direction. Then the initial phase angle ?
0
 
will be. 
 (1) 
6
?
   (2) 
3
?
   (3) 
2
3
?
  (4)  
5
6
?
 
Sol. 4 
 
 
–A
Mean position
A
A
y
2
?
y=  A/2 
Extreme position 
Extreme position 
O
 
The initial phase angle 
0
–
6
?
? ? ? 
        = 
5
6
?
 
25
th
 Feb. 2021 | Shift - 2
PHYSICS 
Page 2


 
 
SECTION  - A 
 
1. Match List I with List II. 
 List I    List II 
(a) Rectifier   (i) Used either for stepping up or stepping down the a.c. 
                    Voltage 
(b) Stabilizer   (ii) Used to convert a.c. voltage into d.c. voltage 
(c) Transformer   (iii) Used to remove any ripple in the rectified output voltage 
(d)  Filter    (iv) Used for constant output voltage even when the input 
voltage or load current change 
Choose the correct answer form the options given below: 
(1) (a)-(ii), (b)- (i), (c)-(iv), (d)-(iii) 
(2) (a)-(ii), (b)- (iv), (c)-(i), (d)-(iii)  
(3) (a)-(ii), (b)- (i), (c)-(iii), (d)-(iv) 
(4) (a)-(iii), (b)- (iv), (c)-(i), (d)-(ii) 
Sol. 2 
(a)Rectifier:- used to convert a.c voltage into d.c. Voltage. 
(b) Stabilizer:- used for constant output voltage even when the input voltage or load current 
change 
(c) Transformer:- used either for stepping up or stepping down the a.c. voltage. 
(d) Filter:- used to remove any ripple in the rectified output voltage. 
  
2. Y = A sin( ?t + ?
0
) is the time – displacement equation of a SHM, At t = 0 the displacement of 
the particle is Y = 
A
2
 and it is moving along negative x-direction. Then the initial phase angle ?
0
 
will be. 
 (1) 
6
?
   (2) 
3
?
   (3) 
2
3
?
  (4)  
5
6
?
 
Sol. 4 
 
 
–A
Mean position
A
A
y
2
?
y=  A/2 
Extreme position 
Extreme position 
O
 
The initial phase angle 
0
–
6
?
? ? ? 
        = 
5
6
?
 
25
th
 Feb. 2021 | Shift - 2
PHYSICS 
 
 
 
3. Two identical spring of spring constant '2K' are attached to a block of mass m  and to fixed 
support (see figure). When the mass is displaced from equilibrium position on either side, it 
executes simple harmonic motion. Then time period of oscillations of this system is: 
 
2k
m
2k
 
(1) 
m
k
?   (2) 
m
2k
?  (3) 
m
2
k
?   (4) 
m
2
2k
? 
Sol. 1 
 
M
2K 2K 
 
Dut to parallel combination K
eff
 = 2k + 2k 
          = 4k 
  
eff
m
T 2
k
m
2
4k
m
T
k
? ?
? ?
? ?
?
 
  
4. The wavelength of the photon emitted by a hydrogen atom when an electron makes a transition 
from n = 2 to n = 1 state is: 
 (1) 194.8 nm  (2) 490.7 nm  (3) 913.3 nm  (4)  121.8 nm 
Sol. 4 
 ?E = 10.2 eV 
 
hc
?
 = 10.2 ev 
 
? ?
hc
10.2 e
? ? 
  = 
12400
Å
10.2
 
 = 121.56 nm 
 ? 121.8 nm 
  
Page 3


 
 
SECTION  - A 
 
1. Match List I with List II. 
 List I    List II 
(a) Rectifier   (i) Used either for stepping up or stepping down the a.c. 
                    Voltage 
(b) Stabilizer   (ii) Used to convert a.c. voltage into d.c. voltage 
(c) Transformer   (iii) Used to remove any ripple in the rectified output voltage 
(d)  Filter    (iv) Used for constant output voltage even when the input 
voltage or load current change 
Choose the correct answer form the options given below: 
(1) (a)-(ii), (b)- (i), (c)-(iv), (d)-(iii) 
(2) (a)-(ii), (b)- (iv), (c)-(i), (d)-(iii)  
(3) (a)-(ii), (b)- (i), (c)-(iii), (d)-(iv) 
(4) (a)-(iii), (b)- (iv), (c)-(i), (d)-(ii) 
Sol. 2 
(a)Rectifier:- used to convert a.c voltage into d.c. Voltage. 
(b) Stabilizer:- used for constant output voltage even when the input voltage or load current 
change 
(c) Transformer:- used either for stepping up or stepping down the a.c. voltage. 
(d) Filter:- used to remove any ripple in the rectified output voltage. 
  
2. Y = A sin( ?t + ?
0
) is the time – displacement equation of a SHM, At t = 0 the displacement of 
the particle is Y = 
A
2
 and it is moving along negative x-direction. Then the initial phase angle ?
0
 
will be. 
 (1) 
6
?
   (2) 
3
?
   (3) 
2
3
?
  (4)  
5
6
?
 
Sol. 4 
 
 
–A
Mean position
A
A
y
2
?
y=  A/2 
Extreme position 
Extreme position 
O
 
The initial phase angle 
0
–
6
?
? ? ? 
        = 
5
6
?
 
25
th
 Feb. 2021 | Shift - 2
PHYSICS 
 
 
 
3. Two identical spring of spring constant '2K' are attached to a block of mass m  and to fixed 
support (see figure). When the mass is displaced from equilibrium position on either side, it 
executes simple harmonic motion. Then time period of oscillations of this system is: 
 
2k
m
2k
 
(1) 
m
k
?   (2) 
m
2k
?  (3) 
m
2
k
?   (4) 
m
2
2k
? 
Sol. 1 
 
M
2K 2K 
 
Dut to parallel combination K
eff
 = 2k + 2k 
          = 4k 
  
eff
m
T 2
k
m
2
4k
m
T
k
? ?
? ?
? ?
?
 
  
4. The wavelength of the photon emitted by a hydrogen atom when an electron makes a transition 
from n = 2 to n = 1 state is: 
 (1) 194.8 nm  (2) 490.7 nm  (3) 913.3 nm  (4)  121.8 nm 
Sol. 4 
 ?E = 10.2 eV 
 
hc
?
 = 10.2 ev 
 
? ?
hc
10.2 e
? ? 
  = 
12400
Å
10.2
 
 = 121.56 nm 
 ? 121.8 nm 
  
 
 
5. In a ferromagnetic material, below the curie temperature, a domain is defined as: 
 (1) a macroscopic region with consecutive magnetic diploes oriented in opposite direction. 
 (2) a macroscopic region with zero magnetization. 
 (3) a macroscopic region with saturation magnetization. 
(4) a macroscopic region with randomly oriented magnetic dipoles. 
Sol. 3 
 In a ferromagnetic material, below the curie temperature a domain is defined as a macroscopic 
region with saturation magnetization. 
  
6. The point A moves with a uniform speed along the circumference of a circle of radius 0.36m and 
cover 30
o
 in 0.1s. The perpendicular projection 'P' form 'A' on the diameter MN represents the 
simple harmonic motion of 'P'. The restoration force per unit mass when P touches M will be: 
 
A
0.1s
N
P
30
o
O
0.36m
M
 
(1) 100 N  (2) 50 N   (3) 9.87 N  (4)  0.49 N 
Sol. 3 
 
A
0.1s
N
P
30
o
O
0.36m
M
 
 The point a covers 30
o
 in  0.1 sec. 
 Means 0.1sec.
6
?
? ? ? ? 
 1 ??
0.1
6
?
 
 2 ? = ?? 
0.1 6
2
?
? ?
?
 
 T = 1.2 sec. 
Page 4


 
 
SECTION  - A 
 
1. Match List I with List II. 
 List I    List II 
(a) Rectifier   (i) Used either for stepping up or stepping down the a.c. 
                    Voltage 
(b) Stabilizer   (ii) Used to convert a.c. voltage into d.c. voltage 
(c) Transformer   (iii) Used to remove any ripple in the rectified output voltage 
(d)  Filter    (iv) Used for constant output voltage even when the input 
voltage or load current change 
Choose the correct answer form the options given below: 
(1) (a)-(ii), (b)- (i), (c)-(iv), (d)-(iii) 
(2) (a)-(ii), (b)- (iv), (c)-(i), (d)-(iii)  
(3) (a)-(ii), (b)- (i), (c)-(iii), (d)-(iv) 
(4) (a)-(iii), (b)- (iv), (c)-(i), (d)-(ii) 
Sol. 2 
(a)Rectifier:- used to convert a.c voltage into d.c. Voltage. 
(b) Stabilizer:- used for constant output voltage even when the input voltage or load current 
change 
(c) Transformer:- used either for stepping up or stepping down the a.c. voltage. 
(d) Filter:- used to remove any ripple in the rectified output voltage. 
  
2. Y = A sin( ?t + ?
0
) is the time – displacement equation of a SHM, At t = 0 the displacement of 
the particle is Y = 
A
2
 and it is moving along negative x-direction. Then the initial phase angle ?
0
 
will be. 
 (1) 
6
?
   (2) 
3
?
   (3) 
2
3
?
  (4)  
5
6
?
 
Sol. 4 
 
 
–A
Mean position
A
A
y
2
?
y=  A/2 
Extreme position 
Extreme position 
O
 
The initial phase angle 
0
–
6
?
? ? ? 
        = 
5
6
?
 
25
th
 Feb. 2021 | Shift - 2
PHYSICS 
 
 
 
3. Two identical spring of spring constant '2K' are attached to a block of mass m  and to fixed 
support (see figure). When the mass is displaced from equilibrium position on either side, it 
executes simple harmonic motion. Then time period of oscillations of this system is: 
 
2k
m
2k
 
(1) 
m
k
?   (2) 
m
2k
?  (3) 
m
2
k
?   (4) 
m
2
2k
? 
Sol. 1 
 
M
2K 2K 
 
Dut to parallel combination K
eff
 = 2k + 2k 
          = 4k 
  
eff
m
T 2
k
m
2
4k
m
T
k
? ?
? ?
? ?
?
 
  
4. The wavelength of the photon emitted by a hydrogen atom when an electron makes a transition 
from n = 2 to n = 1 state is: 
 (1) 194.8 nm  (2) 490.7 nm  (3) 913.3 nm  (4)  121.8 nm 
Sol. 4 
 ?E = 10.2 eV 
 
hc
?
 = 10.2 ev 
 
? ?
hc
10.2 e
? ? 
  = 
12400
Å
10.2
 
 = 121.56 nm 
 ? 121.8 nm 
  
 
 
5. In a ferromagnetic material, below the curie temperature, a domain is defined as: 
 (1) a macroscopic region with consecutive magnetic diploes oriented in opposite direction. 
 (2) a macroscopic region with zero magnetization. 
 (3) a macroscopic region with saturation magnetization. 
(4) a macroscopic region with randomly oriented magnetic dipoles. 
Sol. 3 
 In a ferromagnetic material, below the curie temperature a domain is defined as a macroscopic 
region with saturation magnetization. 
  
6. The point A moves with a uniform speed along the circumference of a circle of radius 0.36m and 
cover 30
o
 in 0.1s. The perpendicular projection 'P' form 'A' on the diameter MN represents the 
simple harmonic motion of 'P'. The restoration force per unit mass when P touches M will be: 
 
A
0.1s
N
P
30
o
O
0.36m
M
 
(1) 100 N  (2) 50 N   (3) 9.87 N  (4)  0.49 N 
Sol. 3 
 
A
0.1s
N
P
30
o
O
0.36m
M
 
 The point a covers 30
o
 in  0.1 sec. 
 Means 0.1sec.
6
?
? ? ? ? 
 1 ??
0.1
6
?
 
 2 ? = ?? 
0.1 6
2
?
? ?
?
 
 T = 1.2 sec. 
 
 
 We know that ? = 
2
T
?
 
  ? = 
2
1.2
?
 
 Restoration force  (F) = m ?
2
A 
 Then  Restoration force per unit mass 
F
m
? ?
? ?
? ?
 = ?
2
A 
  
2
F 2
0.36
m 1.2
? ? ? ? ?
? ?
? ? ? ?
? ? ? ?
 
  ? 9.87 N 
 
 7. The stopping potential for electrons emitted from a photosensitive surface illuminated by light of 
wavelength 491 nm is 0.710 V. When the incident wavelength is changed to a new value, the 
stopping potential is 1.43V. The new wavelength is: 
 (1) 400 NM  (2) 382 nm  (3) 309 nm  (4) 329 nm 
Sol. 2 
 From the photoelectric effect equation  
 
hc
?
 = ? + ev
s
 
 so 
1
s
ev = 
1
hc
? ?
?
 ……(i) 
 
2
s
ev = 
2
hc
? ?
?
 …..(ii) 
 Subtract equation (i) from equation (ii) 
 
1
s
ev – 
2
s
ev = 
1 2
hc hc
?
? ?
 
 
1
s
v –
2
s
v = 
1 2
hc 1 1
e
? ?
?
? ?
? ?
? ?
 
 (0.710 – 1.43) = 1240 
2
1 1
491
? ?
?
? ?
?
? ?
 
 
2
0.72 1 1
1240 491
?
? ?
?
 
 
2
1 1 0.72
491 1240
? ?
?
 
 
2
1
?
 = 0.00203 + 0.00058 
Page 5


 
 
SECTION  - A 
 
1. Match List I with List II. 
 List I    List II 
(a) Rectifier   (i) Used either for stepping up or stepping down the a.c. 
                    Voltage 
(b) Stabilizer   (ii) Used to convert a.c. voltage into d.c. voltage 
(c) Transformer   (iii) Used to remove any ripple in the rectified output voltage 
(d)  Filter    (iv) Used for constant output voltage even when the input 
voltage or load current change 
Choose the correct answer form the options given below: 
(1) (a)-(ii), (b)- (i), (c)-(iv), (d)-(iii) 
(2) (a)-(ii), (b)- (iv), (c)-(i), (d)-(iii)  
(3) (a)-(ii), (b)- (i), (c)-(iii), (d)-(iv) 
(4) (a)-(iii), (b)- (iv), (c)-(i), (d)-(ii) 
Sol. 2 
(a)Rectifier:- used to convert a.c voltage into d.c. Voltage. 
(b) Stabilizer:- used for constant output voltage even when the input voltage or load current 
change 
(c) Transformer:- used either for stepping up or stepping down the a.c. voltage. 
(d) Filter:- used to remove any ripple in the rectified output voltage. 
  
2. Y = A sin( ?t + ?
0
) is the time – displacement equation of a SHM, At t = 0 the displacement of 
the particle is Y = 
A
2
 and it is moving along negative x-direction. Then the initial phase angle ?
0
 
will be. 
 (1) 
6
?
   (2) 
3
?
   (3) 
2
3
?
  (4)  
5
6
?
 
Sol. 4 
 
 
–A
Mean position
A
A
y
2
?
y=  A/2 
Extreme position 
Extreme position 
O
 
The initial phase angle 
0
–
6
?
? ? ? 
        = 
5
6
?
 
25
th
 Feb. 2021 | Shift - 2
PHYSICS 
 
 
 
3. Two identical spring of spring constant '2K' are attached to a block of mass m  and to fixed 
support (see figure). When the mass is displaced from equilibrium position on either side, it 
executes simple harmonic motion. Then time period of oscillations of this system is: 
 
2k
m
2k
 
(1) 
m
k
?   (2) 
m
2k
?  (3) 
m
2
k
?   (4) 
m
2
2k
? 
Sol. 1 
 
M
2K 2K 
 
Dut to parallel combination K
eff
 = 2k + 2k 
          = 4k 
  
eff
m
T 2
k
m
2
4k
m
T
k
? ?
? ?
? ?
?
 
  
4. The wavelength of the photon emitted by a hydrogen atom when an electron makes a transition 
from n = 2 to n = 1 state is: 
 (1) 194.8 nm  (2) 490.7 nm  (3) 913.3 nm  (4)  121.8 nm 
Sol. 4 
 ?E = 10.2 eV 
 
hc
?
 = 10.2 ev 
 
? ?
hc
10.2 e
? ? 
  = 
12400
Å
10.2
 
 = 121.56 nm 
 ? 121.8 nm 
  
 
 
5. In a ferromagnetic material, below the curie temperature, a domain is defined as: 
 (1) a macroscopic region with consecutive magnetic diploes oriented in opposite direction. 
 (2) a macroscopic region with zero magnetization. 
 (3) a macroscopic region with saturation magnetization. 
(4) a macroscopic region with randomly oriented magnetic dipoles. 
Sol. 3 
 In a ferromagnetic material, below the curie temperature a domain is defined as a macroscopic 
region with saturation magnetization. 
  
6. The point A moves with a uniform speed along the circumference of a circle of radius 0.36m and 
cover 30
o
 in 0.1s. The perpendicular projection 'P' form 'A' on the diameter MN represents the 
simple harmonic motion of 'P'. The restoration force per unit mass when P touches M will be: 
 
A
0.1s
N
P
30
o
O
0.36m
M
 
(1) 100 N  (2) 50 N   (3) 9.87 N  (4)  0.49 N 
Sol. 3 
 
A
0.1s
N
P
30
o
O
0.36m
M
 
 The point a covers 30
o
 in  0.1 sec. 
 Means 0.1sec.
6
?
? ? ? ? 
 1 ??
0.1
6
?
 
 2 ? = ?? 
0.1 6
2
?
? ?
?
 
 T = 1.2 sec. 
 
 
 We know that ? = 
2
T
?
 
  ? = 
2
1.2
?
 
 Restoration force  (F) = m ?
2
A 
 Then  Restoration force per unit mass 
F
m
? ?
? ?
? ?
 = ?
2
A 
  
2
F 2
0.36
m 1.2
? ? ? ? ?
? ?
? ? ? ?
? ? ? ?
 
  ? 9.87 N 
 
 7. The stopping potential for electrons emitted from a photosensitive surface illuminated by light of 
wavelength 491 nm is 0.710 V. When the incident wavelength is changed to a new value, the 
stopping potential is 1.43V. The new wavelength is: 
 (1) 400 NM  (2) 382 nm  (3) 309 nm  (4) 329 nm 
Sol. 2 
 From the photoelectric effect equation  
 
hc
?
 = ? + ev
s
 
 so 
1
s
ev = 
1
hc
? ?
?
 ……(i) 
 
2
s
ev = 
2
hc
? ?
?
 …..(ii) 
 Subtract equation (i) from equation (ii) 
 
1
s
ev – 
2
s
ev = 
1 2
hc hc
?
? ?
 
 
1
s
v –
2
s
v = 
1 2
hc 1 1
e
? ?
?
? ?
? ?
? ?
 
 (0.710 – 1.43) = 1240 
2
1 1
491
? ?
?
? ?
?
? ?
 
 
2
0.72 1 1
1240 491
?
? ?
?
 
 
2
1 1 0.72
491 1240
? ?
?
 
 
2
1
?
 = 0.00203 + 0.00058 
 
 
 
2
1
?
 = 0.00261 
 ?
2
 = 383.14 
 ?
2
 ? 382nm 
  
8. A charge 'q' is placed at one corner of a cube as shown in figure. The flux of electrostatic field E
?
 
though the shaded area is: 
 
Z 
q 
Y 
X 
 
(1)
0
q
48 ?
  (2) 
0
q
8 ?
  (3) 
0
q
24 ?
   (4)  
0
q
4 ?
 
Sol. 3 
 ? = 
0
q
24 ?
 
 ?
T
 = 
0 0
q q 1
24 24 2
? ?
? ?
? ?
? ?
? ?
 
 ?
T
 = 
0
q
24 ?
 
  
9. A sphere of radius 'a' and mass 'm' rolls along horizontal plane with constant speed ?
0
. It 
encounters an inclined plane at angle ? and climbs upward. Assuming that it rolls without 
slipping how far up the sphere will travel ? 
 
a
?
0
?
 
(1) 
2
0
2
5 gsin
?
?
  (2) 
2
0
10
7gsin
?
?
  (3) 
2
0
5gsin
?
?
  (4) 
2
0
2gsin
?
?
 
 
 
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